138 BUI.LKTIN 31 138 



pearing in some elongate forms singularly like sylvcerupis , but 

 without the long anterior, and concave lunular margin of that 

 species, therefore approaching vn o\i\X\ue. siibinipressa Con., but 

 with deeper valves and passing gradually through shorter forms 

 (fig. 10 and var. sitbvitrea de Greg., fig. 11) into ty'^xcdX perovata . 



Types. — Paleont. Mus. C. U. 



Horizon. — St. Maurice and Claiborne Eocene. 



Specimens figured. — Paleont. Mus., Cornell Univ. 



Localities. — Lisbon, base of Claiborne Bluff, Ala. ; 3 and 6 

 miles W. N. W. of Orangeburg, S. C. 



Meretrix perovata Con., PI. 43. Figs. 11, 12 a, 13,/ t/-- 



Cytherea perovata Con., Foss. Sh. Tert. Form., Aug., 1833, p. 37. 

 Cytherea coinis Lea, Cont. to Geol., Dec, 1833, p. 66, pi. 2, fig. 41. 

 Diane perovata Con., Jr. Amer. Conch., vol, i, 1865, p. 6. 

 Cytherea cequorea vars. coniis and cominduta de Greg., Mon. Faun. 

 Eoc. Ala., 1890, p. 217, pi. 34, fig. I, 2, 3, 4, 6, 7, 



Conrad'' s original descriptiofi. — Shell cuneiform, ovate, convex, smooth 

 and polished, slightly sulcated on the inferior half of the valves ; posterior 

 side slightly compressed and cuneate ; umbo tumid, beaks almost anterior ; 

 two anterior cardinal teeth in the right valve, approximate and parallel ; 

 lunula cordate and defined by a simple impressed line. Length i}4, inches. 

 Breadth i inch. Claiborne. Cab. Acad., N. S. 



That this is an extremely variable species we are ready to ad- 

 mit, ranging from the tumid, tj'-pical forms with but the peri- 

 pheral beginnings of coarse liration, through more extensively 

 marked, somewhat less inflated specimens called var. aldrichi 

 (pi. 24, figs. I, 2) to the large flat niorto?ii with its strong even 

 concentric lirations. In the Jackson the subvitrea var. is repre- 

 sented by annexa Con. and the aldrichi var. by pearlensis Har. 

 But, that it is a variety of aquorea we seriously question. Greg- 

 orio's cominduta seems to include both mortonidivA our variety 

 aldrichi. 



For a discussion of var. aldrichi Har., see these Bulletins, 

 vol. I. 1895, P- 48, pi- I, fig- I. 



Type. — {Oi perovata, Phila. Acad., of var. aldrichi, Texas 



